1. Field of the Invention
The present invention relates to a novel method for regulating perfusion flow rate and to a novel device for regulating perfusion flow rate.
As is known, the liquid to be perfused is contained in a reservoir which flows through a tubing directly into the vein of the patient, into which a perfusion needle is inserted.
2. Description of the Prior Art
Known perfusion flow rate control devices are usually peristaltic pumps whose flow rate is controlled essentially by roller systems.
However, these peristaltic pumps have numerous drawbacks. In these known devices, even if the flow rate is monitored it is not servocoupled. Moreover, peristaltic pumps can cause flattening of the perfusion reservoir. On the other hand, the peristaltic force is continuously exerted at the same place and over the same distance, so that it causes the customary PVC tubing to loose its elasticity, resulting in its premature wear. This has the result that the use of peristaltic pumps for controlling perfusion flow rate necessitates the use of special tubings having exceptional strength.
In addition, the flow rate is not measured directly: it is equal to the speed of the pump, which makes the calibration of the pump necessary, and consequently, it is subject to the errors or approximations of such calibration.